Direct positive silver halide photographic emulsion

ABSTRACT

A direct positive silver halide photographic emulsion containing a combination of at least one halogen accepting cyanine sensitizing dye represented by the formula:   WHEREIN Z and Z1 each represents non-metallic atomic groups necessary to complete 5- or 6-membered heterocyclic nuclei which may be substituted in other positions except the N-position; R and R1 each represents an alkyl group, a substituted alkyl group of the type normally employed in cyanine dyes, or an aryl group; L1, L2 and L3 each represent a methine group or a substituted methine group, wherein the substituents in two of the substituted methine groups may join and form a ring represented by the following formula:   WHEREIN R6 represents a hydrogen atom or a methyl group and R7 represents a hydrogen atom, an alkyl group, a substituted alkyl group, an aralkyl group, a phenyl group, a substituted phenyl group or a furyl group; p and q each represents 1 or 2; n represents 1, 2 or 3; m represents 1 or 2; and x represents an anion; and at least one compound represented by the formula:   WHEREIN Y represents CH- or N-; R2, R3, R4 and R5 each represents a hydrogen atom, a hydroxy group, an alkoxy group, an aryloxy group, a halogen atom, a heterocyclic nucleus, an alkylthio group, an arylthio group, an amino group, an alkylamino group, a heterocyclylamino group, an aryl group, or a mercapto group; and -A- represents -A1-or -A2-wherein -A1- is WITH THE PROVISO THAT WHEN -A- is -A2- at least one of R2, R3, R4 and R5 is a substituent having a -SO3M group, wherein M has the same meaning as defined above.   WHEREIN M represents a hydrogen atom or a cation which affords water solubility, and wherein -A2- is   D R A W I N G

United States Patent 1191 Shiba et al.

DIRECT POSITIVE SILVER HALIDE PHOTOGRAPHIC EMULSION Inventors: Keisuke Shiba; Masanao Hinata;

Reiichi ()hi; Arkira Sato; Koutarou Yamasue, all of Minami-Ashigara, Japan; Tokiharu Kondo, deceased,

' late of Minami-Ashigara, Japan, by

Yoshiharu Kondo, legal representative Assignee: Fuji Photo Film Co., Ltd., I

Minami-Ashigara, Japan Filed: Aug. 21, 1973 Appl. No.: 390,264

Related U.S. Application Data Continuation-impart of Ser. No. 149,272, June 2, 1971, abandoned.

Foreign Application Priority Data 1 June 3, 1975 [56] References Cited 7 UNITED STATES PATENTS 3,537,858 11/1970 Wise 96/126 3,615,613 10/1971 Shiba et a1. 96/126 3,617,295 11/1971 Shiba et a1. 96/126 3,635,721 1/1972 Sato et al. 96/126 Primary Examiner.l. Travis Brown Attorney, Agent, or Firm-Sughrue, Rothwell, Mion, Zinn and Macpeak [57] ABSTRACT A direct positive silver halide photographic emulsion containing a combination of at least one halogen accepting cyanine sensitizing dye and at least one compound represented by the formula:

The moieties set out above are specifically defined in the specification.

15 Claims, 2 Drawing Figures PATENTEDJUH 3 I975 FIGI :EZmE

logE

FIG. 2

INVENTORS ATTORNEYS 1 DIRECT POSITIVE SILVER HALIDE PHOTOGRAPIIIC EMULSION BACKGROUND OF THE INVENTION I. Field of the Invention The present invention relates to a silver halide photographic emulsion and especially to a direct positive sil ver halide photographic emulsion which is fogged previously.

2. Description of the Prior Art When silver halide photographic materials are exposed to light which includes rays in a range of a sensitizing wave length and developed, the silver densityincreases as the exposure amount increases and reaches to the maximum value. But when the exposure amount further increases, the silver density decreases again to form finally a positive image. Such phenomenon is called generally Solarization. The same inversion phenomenon as that caused by light is observed-in a silver halide which is fogged optically or chemically at preparation thereof.

It is known from U.S. Pat. No. 2,323,187 and Japanese Patent Publication No. 4125/68 that some increase of reversal sensitivity and expansion of a reversal sensitizing wave length range are observed when sensitizing dyes which show a sensitizing function to the common negative-positive type emulsion such as cyanine dyes are added.

It is an important technique in preparation of a direct positive photosensitive material having high sensitivity or a direct positive photosensitive material for color photography to increase further the spectral sensitivity of the direct positive emulsion which is spectrally sensiincreases by adding a compound represented by the following formula to the direct positive silver halide emulsion spectrally sensitized by a cyanine dye Formula (II) N N a M was-bat T km y N M wherein Y represents =CH or =N-, R R R, and R each represents a hydrogen atom, hydroxyl group, alkoxy group, aryloxy group (e.g. phenoxy group, 0- tolyoxy group, p-sulfophenoxy group and B-naphthoxy group), halogen atom (e.g. chlorine atom and bromine atom), heterocyclic nucleus (e.g. morpholinyl group and pyperidyl group), alkylthio group (e.g. methylthio group and ethylthio group), heterocyclylthio group (e.g. benzothiazylthio group), arylthio group (eLg. phenylthio group and tolylthio group), amino group, alkylamino group (eg. methyl-amino group, ethylamino group, propylamino group, dimethylamino group, di ethylamino group, dodecylamino group, cyclohexylamino group, B-hydroxyethylammo group, di-B- hydroxyethylamino group and ,B-sulfoethylamino group), arylamino group or substituted arylamino group (e.g. anilino group, o-sulfoanilino group, msulfoanilino group, p-sulfoanilino group, o-anisylamino group, m-anisylamino group, p-anisylamino group,'otoluidino group, m-toluidino group, p-toluidino group, o-carboxyanilino group, m-carboxyanilino group, pcarboxyanilino group, hydroxyanilino group, naph' thylamino group and sulfonaphthylamino group), heterocyclylamino group (e.g. 2-benzothiazoleamino group and Z-pyridylamino group), aryl group (e.g. phenyl group) and mercapto group, and -A- represents a group selected from the following -A,- and tized by the cyanine dyes. A,.

An object of the present invention is to provide a di- A,-:

SO M M Q- Q s o- SID l-i 1% 50 M 50 M m -u.a- -lHCO- 5 50 i i tD M fl C p-0 and E"' U C :Q

0 25M 1293 uC'jI l rect positive silver halide emulsion containing cyanine dyes, the spectral sensitivity of which is markedly increased.

wherein M represents a hydrogen atom or cation which affords water solubility. -A2

SUMMARY OF THE INVENTION We have found the spectral sensitivity remarkably But when A represents A at least one of R R;,, R, or R is a substituent having an SO M group (M has the same meaning as described above).

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 and FIG. 2 show characteristic curves.

DETAILED DESCRIPTION OF THE INVENTION As the cyanine dyes, any dye may be used if it is effective to the common negative-positive type silver halide emulsion. i.e., halogen accepting sensitizing cyanine dyes. But halogen accepting sensitizing cyanine dyes represented by the following formula (I) are parcularly preferable.

The heterocyclic nuclei formed by Z and Z, include 3 for example, thiazole nuclei such as thiazole, .4.-

methylthiazole, 4-phenylthiazole, S-methylthiazole, 5-

phenylthiazole, 4,5-dimethylthiazole, 4,5- diphenylthiaz ole, 4-(2-thienyl)-thiazole, benzothiazole, 4-chlorobenzothiazole, 5-chlorobenzothiazole, 6- chlorobenzothiazole, 7-chlorobenzothiazole, 5- methylbenzothiazole, -methylbenzothiazole, 5- bromobenzothiazole, S-phenylbenzothiazole, 5- methoxybenzothiazole, 6-methoxybenzothiazole, 5-

ethoxybenzothiaz ole, 5,6-dimethoxybenzothiazole, 5-

hydroxybenzothiazole, 6-hydroxybenzothiazole, naphtho(l,2)-thiazole, naphtho(2,3)-thiazole and naphtho(2,l)th iazole; oxazole nuclei such as 4- methyloxazole, S-methyloxazole, 4-phenyloxazole, 4,5- diphenyloxazole, 4-ethyloxazole, 4,5-dimethyloxazole, 5phenyloxazole, benzoxazole, 5-chlorobenzoxazole,

S-methylbenzoxazole, S-phenylbenzoxazole, 6- methylbenzoxazole, 5,6-dimethylbenzoxazole, 5- methoxybenzoxazole, 5-ethoxybenzoxazole, 5- hydroxybenzoxazole, 6-hydroxybenzoxazole, naphth0(l,2)-oxazole, naphtho(2,3)-oxazole and naphtho( 2, 1 )-oxazole; selenazole nuclei such as 4- methylselenazole, 4-phenylselenazole, benzoselenazole, 5-chlorobenzoselenazole, 5-

methylbenzoselenazole, S-methoxybenzoselenazole, 5-hydroxybenzoselenazole, S-phenylbenzoselenazole, naphtho( l,2)-selenazole and naphtho(2,l )-selenazole; thiazoline nuclei such as thiazoline and 4- methylthiazoline; oxazoline nuclei such as oxazoline; quinoline nuclei such as 2-quinoline nuclei, e.g. quinoline, 3-methylquin0line, S-methylquinoline, 8- methylquinoline, -chloroquinoline, 8- chloroquinoline, 6methoxyquinoline, 6- ethoxyquinoline, -hydroxyquinoline and 8- hydroxyquinoline, 4-quinoline nuclei, e.g. quinoline, 6-methoxyquinoline, 8-methylquinoline, chloroquinoline, 8-chloroquin0line, -fluoroquinoline,

8-fluoroquinoline, fi-hydroxyquinoline, 8 hydroxyquinoline and -methylquinoline, lisoquinoline nuclei, e.g. isoquinoline and 3,4

ample,

dihydroqiiinoline, and 3-isoquinoline nuclei e.g. isoquinoline; benzimidazole nuclei such as 1,3- diethylbenzimidazole, 1,3-diethyl-5- chlorobenzimidazole, l,3-diethyl-5,6- dichlorobenzimidazole and l-ethyl-3- phenylbenzimidazole; and 3,3'-dialkylindolenine nuclei such as 3,3'-dimethylindolenine, 3,3-5- trimethylindolenine and 3,3'-7-trimethylindolenine.

Examples of substituted methine for L,, L and L are represented by the following groups and formulae: =C(-CH3 =c -c2H, =C(-c,.H 1

wherein R represents a hydrogen atom or methyl group, and R represents a hydrogen atom, an alkyl, substituted alkyl, aralkyl, phenyl, substituted alkyl or furyl group.

Alkyl groups in R and R, include, for example, methyl, ethyl, propyl, isopropyl, butyl, hexyl, cyclohexyl, decyl and dodecyl groups.

Substituted alkyl groups in R and R include, for exhydroxy alkyl (e.g. 2-hydroxyethyl, 3- hydroxypropyl), alkoxy alkyl (e.g. Z-methoxyethyl), acetoxy alkyl (e.g. 62-acetoxyethyl, y-acetoxypropyl), carboxy radical-containing alkyl (e.g. carboxymethyl, 2-carboxyethyl, 3-carboxypropyl, 2-(2-carb0xyethoxy)ethyl, p-carboxy benzyl), sulfo radical-containing alkyl (e.g. 2-sulfoethyl, 3-sulfopropyl, 4-sulf0butyl, 2-hydroxy-l-sulfopropyl, 2-(3-sulfopropoxy)ethyl, 2-acetoxy-Lsulf0propyl, 3-methoxy-2-(3-sulfopropoxy)propyl, 2-(2-(3-sulfopropoxy)ethoxy)ethyl, 2- hydroxy-3-(3-sulfopropoxy)-propyl, p-sulfobenzyl, psulfophenethyl) aralkyl (e.g. benzyl, phenylethyl) and allyl group.

Aryl groups for R and R include, for example, phenyl, tolyl, naphthyl, methoxyphenyl and chlorophenyl groups.

Anions of X include, for example, a chlorine ion, bromine ion, iodine ion, thiocyanic ion, sulfonic ion, perchloric ion, p-toluenesulfonic ion, methylsulfuric ion and ethylsulfuric ion.

Though emulsifying and physical ripening of the silver halide emulsion used in the present invention can be practiced by the same method as in the common emulsions, it is more effective to add salts of a metal of Group VIII of the Periodic Table, such as an iridium salt and a rhodium salt at precipitation or during physical ripening.

In case of sensitizing an emulsion containing a rhodium salt by cyanine dyes, more advantageous reversal 5 spectral sensitization is performed as compared with the case that an emulsion which does not contain a rhodium salt is sensitized by a combination of cyanine dyes and desensitizing compounds such as Pinakryptol yellow.

The technique of increasing the spectral sensitivity by using compounds represented by the formula (II) together with cyanine dyes can be applied to an emulsion in which rhodium salts are not used, by which further high sensitivity can be obtained as compared with the case of spectral sensitization by using only cyanine dyes.

0n the other hand, there is a disadvantage that addition of the cyanine dyes at sensitization of the direct positive silver halide emulsion causes increase of reinversion" and enhances the minimum density (D 1min), and consequently, satisfactory whiteness is not obtained sometimes. This phenomenon has a tendency to increase as the amount of the cyanine dyesincreases. lHlerein, re-inversion means the fact that the density increases again after the decrease thereof on the characteristic curve as shown by a dotted line in PK]. 1. although re-invers'ion depends upon a process for preparing the silver halide photographic emulsion, desensitizing compoundssuch as Pinacryptol yellow are effective for lowering re-inversion and the minimum density (D min). However, when Pinacryptol yellow coexists with a cyanine dye in the direct positive silver halide emulsion sensitized by the cyanine dye, there is a disadvantage that the reversal spectral sensitivity also decreases though the re-inversion and the minimum density (D min) is lowered. However, if the compounds represented by the formulatll) used in the present invention coexist with. cyanine dyes, not only is the reversal sensitivity increased but the re-inversion and the minimum density is lowered.

it is preferable usually that the cyanine dyes and the compounds represented by the formula (ll) are added for the cyanine dyes, methanol, ethanol and water are used. As the solvent for the compounds represented by the formula (ll), water, methanol and ethanol are used and, if desired, alkali such as caustic soda is added thereto.

An amount of the cyanine dyes added to the direct positive silver halide photographicemulsion is l-200 mg and preferably 10-100 mg per ll kg of the emulsion. An amount of the compounds represented by the formula (ll) is 5-2000 mg and preferably 10-1000 mg per 1 kg of the emulsion. A preferable ratio by weight of cyanine dyes to compounds (ll) is 125-1250.

As the silver halide emulsion used in the present invention, there are silver chloride, silver bromide, silver chloride bromide, silver chloride iodide, silver bromide iodide and silver chloride bromide iodide. The silver halides used in the present invention are fogged to the maximum density by light or a chemical fogging agent. The chemical fogging agent should fog the silver halides without having an adverse influence upon the emulsion. Such chemical fogging agents used include thiourea dioxide, stannous chloride, formaldehyde and hydrazine etc.

After the foggingoperation, the pH and pAg are, if desired, adjusted, and a solution of thecyanine dyes is added to the emulsion. Then a solution of the, compounds represented by the formula (ll) is added. After stirring well the solution is applied to a support. Any of the cyanine dyes and the compounds represented by the formula (ll) may precede at addition to the emulsion. A mixture of both of them may be added to the emulsion or may be added during ageing after rinsing. Additives usually used, such as a coating assistant and a hardener, may be added to the emulsion. Further, the direct positive emulsion of the present invention is effectively used together with color couplers. For example, couplers represented by the following structural formulae are used. All of these compounds are well to an emulsion as a solution respectively. As the solvent 40 known,

lsxamples or yellow couplers:

(J11 CUUH CODE mucosafl coca cona p. CONHCH CH @NHCOC H 2 2 17 35 l C-Cl;=CH-CH=Cli-CH=C I I I-i c OH mCONHCH CH --NHCOCH ?H C H COOH As the support, glass, films of cellulose derivatives, 20 I 7 films of synthetic resins, baryta paper, water-resistant paper and laiminated paper can be preferably used. 6

In the following, compounds represented by the for- 1 mula (I) are exemplified. r 1;

i c H c H S s I 8 Se Se CH C\ D I m v.

N N -Cn=CH-CH=C I 2 5 2 5 1 c 11 C h I 2 I 9 I S\ Se Se C-CH=LHCH=C\ I N N l C-CH=CH-CH=CH-CH=C\ I I l 40 If N c H c H S H C CH H C CH C-GH=CHCH=CH-CH=C y 5 3 5 i c H5 Compound II 5 Compound II 6 Compound II 7 2 w 1+ H N C N v m H N a N .2 O S w I M C 5 O 2 w I H 2 N C N Compound II .8

SO Na Com pound .il l0 Compound 11 ll $O5Na Compound 11 l2 Compound 11 1L;

Compound 11 16 -mu a k 50,21 J t NIL. W V\ Compound ll l7 iiii The couplers represented by the formula (II) used in the present invention are described in .lap. Pub. No. 10773/68.

In the following, examples of the present invention fixed by a fixing solution containing thiosulfate, rinsing and drying. Determination of the optical density was carried out by a densitometer. In the following, the results are shown in Table 1.

Table 1 Experiment Compound Having Formula Compound Having Formula No. (I)

Amount (mg/kg Em) Amount (mg/kg Em) 1 1 2 (19.7 2 1 2 3 1-2 11-2 400 4 1-2 11-3 400) 5 l2 "-4 (400) 6 l-2 "-5 (400) 7 I2 "-6 (400) 8 I-2 II-7 (400) 9 l-2 "-8 (400) I0 I 6 19.4) ll l-6 ("l Il-8 (400) I2 l-6 "-9 (400) I3 l-6 "-10 (400) 14 1-6 11-11 400) I5 [-6 "-12 (400) I6 l-6 11-13 (400) I7 l-6 II-l4 (400) 18 l-6 11-15 (400) I9 l-6 ll-l6 (400) 20 1- 11 (19.4 2l I-ll ll-l7 (800) 22 I-ll "-18 (800) 23 1-11 11-19 (800) 24 I-ll "-20 (800) are shown. However, the present invention is not lim- Yellovseflsitivity Maximum Density Minimum D y ited in these examples (relative value) (D max) (D min) 100 2.) 0.74 EXAMPLE 1 155 2.0 0.26 t 170 2.0 0.26 A silver chloride iodide bromlde emulsion (iodine: 130 2.0 0.25 1.3 mol and bromine: 21.3 mol was fogged by 3:88 88; formalin. The pH and pAg were adjusted to 5.6 and 6.7 1660 respectively. To this emulsion, dyes represented by the 200 2.0 0.21 formula (I) shown in the following Table l were added %88 8'22 and mixed homogeneously. Compounds represented by 2890 2.2 0.08 the formula (II) were then added. After mixing the mix- 228 8;? ture was applied to a triacetyl cellulose base. In order 1600 to compare, dyes represented by the formula (I) were 205 2.2 0.35 added solely to the above-mentioned fogged emulsion 228 83 and the resulting mixture was applied to a base. After 660 drying, these films were exposed to light through step- 1120 0.15 wedges by a sensitometer. Yellow sensitivity was deter- 2 8%? mined using a Fuji Filter No. 12. 1180 2.1 0.08 After exposing to light the films were developed with 8 8-}; a developing solution having the following formulation.

Experiment Compound Having Formula Compound Having Formula No. I

Amount (mg/kg Em) Amount (mg/kg Em) 25 1-11 (19.4 11-21 (800) 26 I ll "-22 (800) 27 l- 11 1| 23 (800) 28 I-ll II24 (800) Formulation of the Developing soh fion Yellow Sensitivity Maximum Density Minimum Density Mew 4 (relative value) (D max) (D min) 8 Hydroquinone 10 g Anhydrous Sodium Sulfite g Anhydrous Sodium Carbonate 2.5 g Water is added so as to become 1 liter.

After developing, the direct positive images were An emulsion was prepared from the following formuadded to the above mentioned emulsion followed by adding a hardener and a coating assistant. The products latiorm were applied to baryta paper. After drying, these sensit1ve layers were exposed through step-wedgesby a sengelatin p 5 sitometer. After exposing the sensitive layers were 3151' l 81' H Silver Name .1000 g treated by the same procedure as in Example 1. Results Water liter were shown in Table 2.

Table 2 Expgrlment Compound Having Formula Compound Having Formula Amount (mg/kg emulsion) Amount (mg/kg emulsion) 29 1 1 17.8) 30 1-1 (17.8) 11-8 (400 31 1-1 (17.8) 11-8 (800 32 I 3 (20.7) 33 1-3 20.7 11-8 (400 34 1-3 20.7 11-8 (800) 35 I 4 17.3) V 36 1-4 (17.3) 11-8 (400) 37 1-4 (17.3 11-8 (800) 38 1-5 (18.4) 11-8 39 1-5 (18.4) 11-8 (400) 40 1-5 18.4 11-8 (800) 41 1 7 (22.4) 42 1-7 22.4 11-8 (400) 43 1-7 (22.4 11-8 (800) 44 1- 8 (23.4 45 1- 8 (23.4) 11 8 (400 46 1-8 (23.4) 11-8 (800) 47 1- 9 (24.5) I 48 1-9 (24.5 11-8 (400) 49 19 (24.5) "-8 (800) 50 1- 10 (18.3)

I 111 Sodium Chloride 350 g 30 Yellow Sensitivity Maximum Density Minimum Density 0.1% (NH4):l( 1 Solution 200 ml (relative value) (D max) (D min) Water 2 liter IV Gelatin 1700 3,3 0,21 Potassium Iodide 12.7 380 3.3 OLOS Water 7500 ml 390 33 0 05 35 100 3.2 0.28 o 345 3.1 0.08 The Solution III was added to the Solution I at 40 C 340 30 with stirring and then adding the Solution 11 thereto. 100 After 20 minutes, the Solution 1v was added and the 31g 3;; 8; pH was adjusted to 9.0 by adding an alkali. The emul- 100 3.3 0.31 sion was fogged by hydrazine dihydrochloride. In this 40 23 8-82 emulsion, the ph and pAg were adjusted to 5.6 and 6.7, 100 0113 respectively. Dyes represented by the formula (I) g8; 882 shown in the following Table 2 were admixed with the 100 above mentioned emulsion. Compounds represented 445 3.2 0.06 by the formula (II) were then added thereto, followed 45 1'38 8:28 by adding a hardener and a coating assistant thereto. 280 3.1 0.08 The products were applied to a baryta paper. In order %8 8-92 to compare, dyes represented by the formula (I) were Experiment Compound Having Formula Compound Having Formula Amount (mg/kg emulsion) Amount (mg/kg emulsion) Yellow Sensitivity Maximum Density Minimum Density C ti d l D (rekmve Va ue) max) (D mm) Yellow Sensitivity Maximum Dens1ty Minimum Density 410 33 005 (relative value) :88 88 670 3.2 0.09 5 100 3.2 0.18 2050 3.2 0.07 510 3 0 07 2100 3.2 0.07 550 '5 100 29 0.36 205 2.9 0.10 200 2.9 0.10 FIG. 2 shows caracteristlc curves wherem curves 2 128 8'85 and 3 correspond to Experiment No. 32 and 33 in 510 2.9 0.08 10 Table 2. 100 3.2 0.16 190 3.2 0.07 EXAMPLE 3 175 3.1 0.07 I00 '3 A silver chloride iodide bromide emulsion (iodine: Q2 3;; 1.3 mol and bromine 21.3 mol was fogged by for- 100 3.1 0.50 malin and the pH and pAg were adjusted to 5.6 and 6.7, 3288 8'8; respectively. This emulsion contained a rhodium salt 100 32 0.62 which was added at formation thereof. i 882 To the above mentioned emulsion, compounds represented by the formula (11) shown in the following Experiment Compound Having Formula Compound Having Formula Amount (mg/kg emulsion) Amount (mg/kg emulsion) 74 1- 19 (18.4) 75 1-19 (18.4 11-4 (401) 76 ll9 (18.4) "-4 (800) 77 l (22.9) 78 1-2() (22.9 11-4 (400 79 1- 20 (22.9) l1 4 (800) 80 I- 21 (25.9) 81 1-21 (25.9 11-4 (400 82 l-Zl (25.9) "-4 (800) 83 l 22 (28.0) 84 l- 22 (28.0) 11 4 (400) 85 1-22 (28.0) "-4 r (800) 86 l 23 (30.7) 87 l-23 (30.7) 114 (400) 88 l-23 (30.7) 11-4 (800) 89 l 24 (24.0) 90 1- 24 (24.0) 11 4 (400) 3, 91 1-24 (24.0) "-4 (800) 92 l (22.0) 93 1- 25 (22.0) 11 4 (400) 94 l- 25 (22.0) 11 4 (800) 95 l 26 (15.8) 96 l-26 (15.8) 114 (400) 97 [-26 (15.8) "-4 (800) Yellow Sensitivity Maximum Density Minimum Density Table 3 were added. Then, dyes represented by the formula (l), dispersions of couplers having the following formula (III) and a hardener were added in turn thereto. The products were applied to a triacetyl cellulose base. In order to compare, dyes represented by the formula (11), a dispersion of a coupler having the above mentioned formula l2) and a hardener were added in turn to the above mentioned emulsion. The product was applied to a base. After drying these films were exposed to light through step-wedges under a yellow filter (Fuji Filter No. 12 (Fuji is registered trade mark)).

After exposing, the samples were developed with using a color developing solution. The films were then treated by fixing, rinsing, bleaching, rinsing, hardening, rinsing and stabilizing in turn.

The results are shown in Table 3.

As is clear from the data contained in the abovementioned Table 1-3, if the halogen accepting sensitizing cyanine dyes represented by the formula (I) are added together with the compounds represented by the formula (II) to the emulsion, direct positive silver hal ide emulsions (sensitive material) having a remarkably high yellow sensitivity and a comparatively low maximum density are obtained as compared with emulsions containing only the cyanine dyes.

What is claimed is: 7

l. A direct positive silver halide photographic emulsion comprising fogged silver halide and a combination of at least a sensitizing halogen accepting cyanine dye represented by the formula (I) wherein Z and Z. each represents nonmetal atoms necessary to complete a thiazole nucleus. an oxazle nucleus, a selenazole nucleus, a thiazoline nucleus, an oxazoline nucleus, a quinoline nucleus, an isoquinoline nucleus, a benzimidazole nucleus, or a 3,3 dialkylindolenine nucleus, R and R, each represents an alkyl group or an aryl group, L L and L each represents a methine group, p and q each represents 1 or 2, n represents 1, 2 or 3, m represents 1 or 2, and X represents an anion, together with at least a compound represented by the following formula (ll) N Y R NH A Mi I QI- N N Y wherein Y represents =CH- or =N-; R R R and R each represents a hydrogen atom, a hydroxy group, an alkoxy group, an aryloxy group, a halogen atom, a heterocyclic nucleus, an alkylthio group. heteracryclothia group an arylthio group, an amino group, an alkylamino group, arylamins group a heterocycloamino group, an aryl group or a mercapto group; and A represents A or -A wherein -A, is

JQZ

wherein M represents a hydrogen atom or a cation which affords water solubility, and wherein A is w|th the proviso that when A represents -A,--, at least one of R R R and R is a substitutent contain ing a -SO M group, in which M is as described above.

2. A direct-positive silver halide photographic emulsion according to claim 1, wherein the amount of the cyanine dye is within the range of 1-200 mg per l lig' of the emulsion.

3. A direct-positive silver halide photographic emulsion according to claim 1, wherein the amount of the compound represented by the formula (II) is within the range of 5-2000 mg per 1 kg of the emulsion.

4. A direct-positive silver halide photographic emulsion according to claim 1, wherein the ratio by weight of the cyanine dye to the compound (ll) is l:5-l:50.

5. A dirct-positive silver halide photographic emulsion according to claim 1, wherein said heterocyclic nucleus formed by Z and Z, is a thiazole nucleus, an oxazole nucleus, a selenazole nucleus, a thiazoline nucleus, an oxazoline nucleus, a quinoline nucleus, an isoquinoline nucleus, at benzimidazole nucleus, or a 3.3- dialkylindolenine nucleus.

6. A direct positive silver halide photographic emulsion according to claim 5, wherein the heterocyclic nucleus formed by Z and Z is thiazole, 4-methylthiazole, 4-phenylthiazole, 5methylthiazole, S-phenylthiazole,

4,5-dimethylthiazole, 4,5-diphenylthiozole, 4-(2- thienyl)-thiazole, benzothiazole, 4- chlorobenzothiazole, 5-chlorobenzothiazole, 6- chlorobenzothiazole, 7-chlorobenzothiazole, 5- methylbenzothiazole, 6-methylbenzothiazole, 5 bromobenzothiazole, S-phenylbenzothiazole, 5- methoxybenzothiazole, 6-methoxybenzothiazole, 5-

ethoxybenzothiazole, 5,6-dimethoxybenzothiazole, 5- hydroxybenzothiazole, 6-hydroxybenzothiazole, naphtho( l,2)-thiazole, naphtho(2,3)-thiazole, naph tho(2,l )-thiazole, 4-methyloxazole,, S-methyloxazole, 4-phenyloxazole, 4,5-diphenyloxazole, 4-ethyloxazole, 4,5-dimethyloxazole, S-phenyloxazole, benzoxazole, S-chlorobenzoxazole, S-methylbenzoxazole, 5- phenylbenzoxazole, 6-methylbenzoxazole, 5,6-dimethylbenzoxazole, S-methoxybenzoxazole, 5- ethoxybenzoxazole, S-hydroxybenzoxazole, 6- hydroxybenzoxazole, naphtho( 1,2)-oxazole, naphtho(2,3 )-oxazole, naphtho(2,l ))-oxazole, 4- methylselenazole, 4-phenylselenazole, benzoselenazole, ichlorobenzoselenazole, 5-

methylbenzoselenazole,, 5-methoxybenzoselenazole, naphtho( 1 ,2)-selenazole, naphtho(2,l )-selenazole, thiazoline, 4-methylthiazoline, oxazoline, 2-quinoline nuclei slected from the group consisting of quinoline, 3-

methylquinoline, S-methylquinoline, 8- methylquinoline, 6-chloroquinoline, 8- chloroquinoline, 6-methoxyquinoline, 6- ethoxyquinoline, 6-hydroxyquinoline, and 8- hydroxyquinoline, 4-quinoline nuclei selected from the group consisting of quinoline, -methoxyquinoline, 8- methylquinoline, 6-chloroquinoline, 8- chloroquinoline, 6-fluoroquinoline, 8-fluoroquinoline, 6-hydroxyquinoline, 8-hydroxyquinoline, and 6- methylquinoline, l-isoquinoline nuclei selected from the group consisting of isoquinoline, and 3,4-

dihydroquinoline, 3-isoquinoline, 1,3- diethylbenzimidazole, 1,3-diethyl-5- chlorobenzimidazole, 1,3-diethyl-5 ,6-

dichlorobenzimidazole, l-ethyl-3- phenylbenzimidazole, 3,3-dimethylindolenine, 3,3-5- trimethylindolenine, or 3,3-7-trimethylindolenine.

7. A direct-positive silver halide photographic emulsion according to claim 1, wherein said alkyl group for R and R is a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a hexyl group, a cyclohexyl group, a decyl group, or a dodecyl group.

8. A direct-positive silver halide photographic emulsion according to claim 1, wherein said alkyl group for R and R is a substituted alkyl group selected from the group consisting of a hydroxyalkyl group, an alkoxyalkyl group, an acetoxyalkyl group, a carboxy radicalcontaining alkyl group, a sulfo radical containing alkyl group, an aralkly group, and an allyl group.

9. A direct-positive silver halide photographic emulsion according to claim 8, wherein said hydroxyalkyl group is a Z-hydroxyethyl group or a 3-hydroxypropyl group, wherein said alkoxyalkyl group is a 2- methoxyethyl group, wherein said acetoxyalkyl group is a ,B-acetoxyethyl group or a 'y-acetoxypropyl group, wherein said carboxy radical-containing alkyl group is a carboxy methyl group,, a Z-carboxyethyl group, a

3-carboxypropyl group, a 2-(2-carboxyethoxy)-ethyl group, or a p-carboxybenzyl group, wherein said sulforadical-containing alkyl group is a 2-sulfoethyl group, a 3-sulfopropyl group, a 4-sulfobutyl group, a 2-hydroxy-1sulfopropyl group, a 2-(3-sulfopropoxy)ethyl group, a 2-acetoxy-lsulfopropyl group, a 3- methoxy-2-(3-sulfopropoxy)propyl group, a 2-(2-(3- sulfopropoxy)ethoxy)ethyl group, a 2-hydroxy-3-(3'- sulfopropoxy)-propyl group, a psulfobenzyl group, or a p-sulfophenethyl group, and wherein said aralkyl group is a benzyl group or a phenethyl group.

10. A direct positive silver halide photographic emulsion of claim 1, wherein said aryl group for R and R is a phenyl group, a tolyl group, a naphthyl group, a methoxyphenyl group, or a chlorophenyl group.

11. A direct positive silver halide photographic emulsion of claim 1, wherein said X is a chlorine ion, a bromine ion, an iodine ion, a thiocyanic ion, a sulfonic ion, a perchloric ion, a p-toluenesulfonic ion, a methylsulfuric ion, or an ethylsulfuric ion.

12. A direct positive silver halide photographic emulsion according to claim 1, wherein said methine group for L L and L is =C(CH =C(C H 3 1), 2 6 5) v 6 5), =C(alkoxy), =C(aryloxy), =C(-Salkyl), =C(O-acyl), =C(-amido), =C(Cl) and =C(-Br), and wherein the substituents of two methine groups of L L and L may bond together to form a ring represented by the following formula wherein R is a hydrogen atom or methyl group, and R is a hydrogen atom, an alkyl group, an aryl group, a phenyl group or a furyl group.

13. A direct-positive silver halide photographic emulsion according to claim 1, wherein the cyanine dyes are selected from the group consisting of 

1. A DIRECT POSITIVE SILVER HALIDE PHOTOGRAPHIC EMULSION COMPRISING FOGGED SILVER HALIDE AND A COMBINATION OF AT LEAST A SENSITIZING HALOGEN ACCEPTING CYANINE DYE REPRESENTED BY THE FORMULA (1)
 1. A direct positive silver halide photographic emulsion comprising fogged silver halide and a combination of at least a sensitizing halogen accepting cyanine dye represented by the formula (I)
 2. A direct-positive silver halide photographic emulsion according to claim 1, wherein the amount of the cyanine dye is within the range of 1-200 mg per 1 kg of the emulsion.
 3. A direct-positive silver halide photographic emulsion according to claim 1, wherein the amount of the compound represented by the formula (II) is within the range of 5-2000 mg per 1 kg of the emulsion.
 4. A direct-positive silver halide photographic emulsion according to claim 1, wherein the ratio by weight of the cyanine dye to the compound (II) is 1:5-1:50.
 5. A dirct-positive silver halide photographic emulsion according to claim 1, wherein said heterocyclic nucleus formed by Z and Z1 is a thiazole nucleus, an oxazole nucleus, a selenazole nucleus, a thiazoline nucleus, an oxazoline nucleus, a quinoline nucleus, an isoquinoline nucleus, a benzimidazole nucleus, or a 3,3''-dialkylindolenine nucleus.
 6. A direct positive silver halide photographic emulsion according to claim 5, wherein the heterocyclic nucleus formed by Z and Z1 is thiazole, 4-methylthiazole, 4-phenylthiazole, 5-methylthiazole, 5-phenylthiazole, 4,5-dimethylthiazole, 4,5-diphenylthiozole, 4-(2-thienyl)-thiazole, benzothiazole, 4-chlorobenzothiazole, 5-chlorobenzothiazole, 6-chlorobenzothiazole, 7-chlorobenzothiazole, 5-methylbenzothiazole, 6-methylbenzothiazole, 5-bromobenzothiazole, 5-phenylbenzothiazole, 5-methoxybenzothiazole, 6-methoxybenzothiazole, 5-ethoxybenzothiazole, 5,6-dimethoxybenzothiazole, 5-hydroxybenzothiazole, 6-hydroxybenzothiazole, naphtho(1,2)-thiazole, naphtho(2,3)-thiazole, naphtho(2,1)-thiazole, 4-methyloxazole,, 5-methyloxazole, 4-phenyloxazole, 4,5-diphenyloxazole, 4-ethyloxazole, 4,5-dimethyloxazole, 5-phenyloxazole, benzoxazole, 5-chlorobenzoxazole, 5-methylbenzoxazole, 5-phenylbenzoxazole, 6-methylbenzoxazole, 5,6-dimethylbenzoxazole, 5-methoxybenzoxazole, 5-ethoxybenzoxazole, 5-hydroxybenzoxazole, 6-hydroxybenzoxazole, naphtho(1,2)-oxazole, naphtho(2,3)-oxazole, naphtho(2,1))-oxazole, 4-methylselenazole, 4-phenylselenazole, benzoselenazole, 5-chlorobenzoselenazole, 5-methylbenzoselenazole,, 5-methoxybenzoselenazole, naphtho(1,2)-selenazole, naphtho(2,1)-selenazole, thiazoline, 4-methylthiazoline, oxazoline, 2-quinoline nuclei slected from the group consisting of quinoline, 3-methylquinoline, 5-methylquinoline, 8-methylquinoline, 6-chloroquinoline, 8-chloroquinoline, 6-methoxyquinoline, 6-ethoxyquinoline, 6-hydroxyquinoline, and 8-hydroxyquinoline, 4-quinoline nuclei selected from the group consisting of quinoline, 6-methoxyquinoline, 8-methylquinoline, 6-chloroquinoline, 8-chloroquinoline, 6-fluoroquinoline, 8-fluoroquinoline, 6-hydroxyquinoline, 8-hydroxyquinoline, and 6-methylquinoline, 1-isoquinoline nuclei selected from the group consisting of isoquinoline, and 3,4-dihydroquinoline, 3-isoquinoline, 1,3-diethylbenzimidazole, 1,3-diethyl-5-chlorobenzimidazole, 1,3-diethyl-5,6-dichlorobenzimidazole, 1-ethyl-3-phenylbenzimidazole, 3,3''-dimethylindolenine, 3,3''-5-trimethylindolenine, or 3,3''-7-trimethylindolenine.
 7. A direct-positive silver halide photographic emulsion according to claim 1, wherein said alkyl group for R and R1 is a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a hexyl group, a cyclohexyl group, a decyl group, or a dodecyl group.
 8. A direct-positive silver halide photographic emulsion according to claim 1, wherein said alkyl group for R and R1 is a substituted alkyl group selected from the group consisting of a hydroxyalkyl group, an alkoxyalkyl group, an acetoxyalkyl group, a carboxy radical-containing alkyl group, a sulfo radical containing alkyl group, an aralkly group, and an allyl group.
 9. A direct-positive silver halide photographic emulsion according to claim 8, wherein said hydroxyalkyl group is a 2-hydroxyethyl group or a 3-hydroxypropyl group, wherein said alkoxyalkyl group is a 2-methoxyethyl group, wherein said acetoxyalkyl group is a Beta -acetoxyethyl group or a gamma -acetoxypropyl group, wherein said carboxy radical-containing alkyl group is a carboxy methyl group,, a 2-carboxyethyl group, a 3-carboxypropyl group, a 2-(2-carboxyethoxy)-ethyl group, or a p-carboxybenzyl group, wherein said sulforadical-containing alkyl group is a 2-sulfoethyl group, a 3-sulfopropyl group, a 4-sulfobutyl group, a 2-hydroxy-1-sulfopropyl group, a 2-(3-sulfopropoxy)ethyl group, a 2-acetoxy-1-sulfopropyl group, a 3-methoxy-2-(3-sulfopropoxy)propyl group, a 2-(2-(3-sulfopropoxy)ethoxy)ethyl group, a 2-hydroxy-3-(3''-sulfopropoxy)-propyl group, a p-sulfobenzyl group, or a p-sulfophenethyl group, and wherein said aralkyl group is a benzyl group or a phenethyl group.
 10. A direct positive silver halide photographic emulsion of claim 1, wherein said aryl group for R and R1 is a phenyl group, a tolyl group, a naphthyl group, a methoxyphenyl group, or a chlorophenyl group.
 11. A direct positive silver halide photographic emulsion of claim 1, wherein said X is a chlorine ion, a bromine ion, an iodine ion, a thiocyanic ion, a sulfonic ion, a perchloric ion, a p-toluenesulfonic ion, a methylsulfuric ion, Or an ethylsulfuric ion.
 12. A direct positive silver halide photographic emulsion according to claim 1, wherein said methine group for L1, L2, and L3 is C(-CH3)-, C(-C2H5)-, C(-C3H7)-, C(-CH2C6H5)-, C(-C6H5)-, C(-alkoxy)-, C(aryloxy)-, C(-S-alkyl)-, C(-O-acyl)-, C(-amido)-, C(-Cl)- and C(-Br)-, and wherein the substituents of two methine groups of L1, L2 and L3 may bond together to form a ring represented by the following formula
 13. A direct-positive silver halide photographic emulsion according to claim 1, wherein the cyanine dyes are selected from the group consisting of
 14. A direct-positive silver halide photographic emulsion according to claim 1, wherein the compound (II) is selected from the group consisting of 